Capacitive touch panels have become commonly used as input devices for a variety of types of electronic devices (e.g., cellular telephones, tablet computers, laptop computers, computer monitors, etc.). Capacitive touch panels generally operate by sensing a change in the electrostatic field generated by conductors (e.g., transparent conductors) separated by an insulator (e.g., glass or other non-conductive substrate). When one of the conductors is contacted by an external conductive body, the capacitive touch panel is affected (i.e., the electrostatic field generated by the conductors and insulator is altered). The change in the electrostatic field is measured as a change in capacitance. For example, the change in capacitance may be detected by electronics provided with the capacitive touch panel such that the occurrence of, and the location of, the contact between the external conductive body and the capacitive touch panel may be determined and interpreted as an input. However, a non-conductive body in contact with one of the conductors will not alter the electrostatic field, and thus will not be sensed (i.e., will not affect the capacitive touch sensor). Because capacitive touch panels may be constructed of substantially transparent components, capacitive touch panels are often used in conjunction with displays to create a capacitive touch screen that serves simultaneously as a display and input device.
Because the human body is a conductor, contact of the skin of an individual may affect a capacitive sensor of a capacitive touch panel (i.e., alter the electrostatic field of the capacitive sensor sufficiently such that the change in capacitance can be interpreted as an input). In this regard, the use of capacitive touch sensors may not require the use of a stylus or other object to affect the sensor as may be the case with some other types of touch panels (e.g., resistive touch panels).
However, the anatomy of the fingers of different individuals may vary widely. For example, some individuals may have large fingers. Accordingly, in the case of a capacitive touch screen, a large portion of the display may be obstructed by the user's finger when the finger is used to contact the capacitive touch screen. Also, a user with a large finger may have difficulty selecting a desired portion of the screen as part of an input because the individual's finger may be larger than the target the user is attempting to manipulate on the graphical user interface of the device.
Furthermore, individuals with fingernails that extend significantly beyond the distal end of the finger tip may have difficulty in manipulating a capacitive touch panel. The conductivity and/or size of the user's fingernail in contact with the capacitive touch panel may be insufficient to affect the capacitive sensor or the touch panel, thus preventing the user from manipulating the capacitive sensor with the user's fingernail. For example, while the fingernail of a user may be conductive, the size of the fingernail at the distal edge thereof may be insufficient to produce a response by a capacitive touch panel. Accordingly, such users may have to contact the capacitive touch panel with the pad of the finger rather than the distal tip of the finger. Accordingly, the problems addressed above with regard to individuals with large fingers may be experienced by individuals with relatively long fingernails as the pad of the user's finger may be substantially larger than the distal tip of the user's finger.
Attempts have been made to develop capacitive styluses for use with capacitive touch panels. However, a number of drawbacks are present in previous capacitive styluses. For example, stylus devices resembling a traditional writing instrument have been proposed. As such, a user may hold such a stylus device like a traditional writing instrument for use with a capacitive touch panel. However, many graphical user interfaces of devices employing capacitive touch panels have been specifically designed to take advantage of the use of an individual's finger or fingers to manipulate the capacitive touch panel. In this regard, a stylus held like a traditional writing instrument may impede the ability of the user to take advantage of these graphical user interfaces. For example, the functionality of the graphical user interface may be specifically designed to take advantage of the use of the individual's fingers to manipulate the capacitive touch panel (e.g., with specifically designed keyboard layouts, controls, menus, etc.). Additionally, user interfaces may employ touch gestures such as pinching motions or other multi-touch gestures. Furthermore, some such styluses include a round tip shape that may obscure a significant portion of the display when in use. Accordingly, styluses shaped as traditional writing instruments tend to limit the user's ability to take advantage of features specifically designed for manipulation of the capacitive touch panel with the user's finger and may still be subject to the problem of screen obstruction.